Pulverized fuel burner



Patented May 29, 1934 PULVERIZED FUEL BURNER Mellen C. M. Hatch, Boston, Mass., assignor to The Standard Stoker Company, Incorporated, a corporation of Delaware Application March 25, 1932, Serial No. 601,181

' 7 claims. (o1. 11o-104) This invention relates to pulverized fuel burners used in connection with furnaces or combustion chambers. l

a l It is the main object of this invention to prol Vide a fuel burner in which pulverized fuel is propelled by` a vehicular air current into a mixing chamber, there `thepulverized fuel being intimately mixed with additional oxygen and then introduced into thelfurnace in thin sheets,be- 105 tween such sheets of pulverized'fuel there is permitted to circulate a current of air (oxygen) necessary for the ignition and the complete combustion of the fuel.'

`It is also an object of this invention to provide in ^afpulverized fuelburner having a mixing chamber as described, a discharge portion of a burner having a series of vertically spaced' and laterally extending passages which communicate with the furnace and the mixing chamber at l"2d theirends, the dischargeportion being further provided with a series of air passagesinterposed between said fuel passageswhich air passages open laterally to atmophere. and forwardly into the furnace. -Afurther object of this invention is the provision in a burner having a mixingchamber and Va discharge portion asdescribed, of a plurality of vertically aligned walls which divide and further separate'lthe fuel passages intoV groups or sections, and the provision `of deflector members which serve to direct the fuel through the Yseparated fuel passages,A which deilectors are also capable'of partially or wholly closing the communication between 'the `separated fuel passages and the mixingchamber. 1 These and other objects and advantages reside in the improved construction ofthe novel pulverized fuel burner and in the method of burning pulverized fuel as will hereinafter be claimed `and described in the following specification which is accompaniedby the drawing, in which Fig. 1 is `a view partly in plan and partly in ,section ofthe burner with a portion ofthe furnaceshown in section; Y

l Fig; 2 is'a side elevation of the burner and Fig. `3 is a transverse section takenon the line "3-3 of Figure 1. v For convenience in the description and the claims,xthe term forward` isemployed toindicate the Vdischarge `end of the burner, and the Aterrn rearward= is used to indicate the intake end thereof. u ..1 v Y The pulverizedgfuel burnerillustrated in the drawing, comprises atubularrearward member i through which fuel is propelled into a forwardly and laterallyared mixing chamber 11 fromwhere it is discharged through the relatively wide exhaust forward end 12 into the furnace 13. The exhaust endl2 ofI the. burner B communicates with-the ring opening 14 in the furnace wall 15 60' and is attached to said wall by the flanges 16.

The pulverized fuel is propelled through the burner B by swiftly moving currents of air generated `by a suitable blower, not shown. This vehicular air, as it is sometimes termed, is insuicient for the complete combustion of the pulverized fuel, `and therefor, means are provided for the admission of the necessary amount of air (or oxygen) as the fuel stream is propelled through the burner VB. For this purpose, the 0 tubular rearward member 10 is provided with a bell-shaped flange 17 which skirts a portion of the mixing chamber wall 18 formed with the tubular` rearward portion 10. The wall 18 is apertured circumferentially as at 19, allowing air 7" to be drawn into the mixing chamber 11 as the pulverized fuel is propelledv through the burner. The tubular rearward member 10 is formed with aneck 20, the throat 2l of `which is provided with a series of spiral ribs 22, spaced circumferentially in said throat 21. The aperture 19 of 'the' wall 18 is at a point rearward of the delivery end of the throat 21. Thepulverized fuel'particles, as .they are propelled through the throat 21, are agitated by the whirling action given them by the spiral'rbs 22'and then pass into the mixing Vchamber 11 in an eddy-like formation, allow- `ing the fuel particles to bel intimately. mixed with the air drawn through the apertures 19.

This invention further contemplates the issuance of such mixed fuel particles from the burner in thin sheets and introducing` a current of air between such sheets so that the pulverized fuel may more readily: ignite and alsoso that the fuel may be completely consumed. To this end,

lthe discharge forward portion 12 of the burner is and rearward ends with' the furnace 13 andthe Amixing chamber llrespectively.

The air passages 25 are separated from the mixing chamber 11 by the transversely extending wap .105? 26 through which pass the fuel passages 24. The

air passages at their forward ends communicate lwith the furnace 13 and open sidewardlyintc atmosphere. Thefuel passages 24, if desired-may be divided into groups or sections'27 `bythe longitudinally extending vertically aligned walls 28, so that when it is desired to operate the furnace at a low capacity, several of these sections 27 may be Wholly or partly closed, as will presently appear.

Immediately rearward of the transverse wall 26 are the deflector members 29 and 30, each of which is pivotally mounted as at 31 to swing angularly about a vertical axis. The deflectors 29 and 30 may be in any desired position as controlled by the handles 32 which are engageably mounted within the arcuate channels 33 by the hand nuts 34. When the hand nut 34 is loosened, the corresponding deflector may then be moved to the desired position by the handle 32 and locked in such position by tightening the hand nut.

In the operation of this device, the pulverized fuel is propelled by vehicular air through the throat 21 into the mixing chamber 1l. Air, which is drawn through the apertures 19, is intimately mixed with the pulverized fuel, agitated by the spiral ribs 22 and then the fuel passes through the flat, divided fuel passages 24. The fuel is introduced into the furnace in thin, separated sheets, between which sheets currents of air are introduced by the air passages 25. The fuel thus discharged is supplied with the proper amount of air necessary for the ignition and complete combustion of the fuel. Should it be desired to give angular direction to the fuel, the deiiector 29 or 30 may be set at the desired angle by manipulating the proper handle 32, or, the deiiectors may be set in the position substantially as shown in Figure 1, whereby all of the fuel is directed to pass through only one group or section 27 of the fuel passages.

From the foregoing, it will be apparent that a novel pulverized fuel burner has been provided which will efficiently mix the fuel with combustion air and which discharges the fuel into the furnace, supplying air necessary for the combustion of the fuel at the forward end of the burner.

I claim:

1. In combination with a furnace having a ring opening in a Wall thereof, a pulverized fuel burner arranged to discharge fuel into the furnace through said ring opening, said pulverized fuel burner comprising a mixing chamber, a tubular member delivering pulverized fuel to and through said mixing chamber, and a discharge portion, said tubular member having a throat communicating with said mixing chamber, a series of spirally formed ribs spaced circumferentially in said throat for agitating the pulverized fuel as the same is propelled through said burner, a wall of said mixing chamber being apertured for admitting air thereto, and a plurality of partitionplates dividing said discharge portion into a plurality of flat, alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their discharge and intake ends with the furnace and said mixing chamber respectively, said air passages communicating With the atmosphere and arranged to discharge into the furnace through said discharge portion, a plurality of Walls dividing said passages for the mixture of fuel and air into groups, and a wall separating the air passages from said mixing chamber.

2. In combination with a furnace having a firing opening in a wall thereof, a pulverized fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising amixing chamber, a rearward tubular member delivering pulverized fuel to and through said mixing chamber, means for agitating the pulverized fuel as the same is propelled into and through said mixing chamber, means arranged for the admission of air to said mixing chamber, a discharge forward portion, a plurality of partition plates dividing said discharge forward portion into a plurality of flat, horizontally disposed, alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their forward and rearward ends with the furnace and said mixing chamber respectively, said air passages communicating With atmosphere and at their forward ends arranged to discharge into the furnace at the forward end of said discharge portion, a plurality of longitudinally extending, vertically aligned walls dividing said fuel passages into groups, a transversely extending vertical Wall separating the air passages from said mixing chamber, and a plurality of vertically disposed defiector members pivotally mounted in said mixing chamber and arranged to variably restrict and direct the discharge of pulverized fuel from said mixing chamber through the plurality of fuel passages of the several groups.

3. In combination with a furnace having a firing opening in a wall thereof, a pulverized fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising a mixing chamber, a tubular member delivering pulverized fuel to and through said mixing chamber, a discharge portion, said tubular member having a throat communicating with said mixing chamber, a series of spirally formed ribs spaced circumferentially in said throat for agitating the pulverized fuel as the same is propelled through said burner, a wall of said mixing chamber being apertured for admitting air thereto, a plurality of partition plates dividing said discharge portion into a plurality of fiat alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their discharge and intake ends with the furnace and said mixing chamber respectively, said air passages communicating with the atmosphere and arranged to discharge into the furnace through said discharge portion, a plurality of walls dividing said passages for the mixture of fuel and air into groups, a wall separating the air passages from said mixing chamber and a plurality of deflector members pivotally mounted in said mixing chamber and arranged to variably restrict and direct the discharge of pulverized fuel from said mixing chamber through the plurality of passages for the mixture of fuel and air of the several groups.

4. In combination with a furnace having a ring opening in a wall thereof, a pulverized fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising a mixing chamber, a tubular member delivering pulverized fuel to and through said mixing chamber, a discharge portion, said tubular member having a throat communicating with said mixing chamber, a series of spirally formed ribs spaced circumferentially in said throat for agitating the pulverized fuel as the same is propelled through said burner, a wall of said mixing chamber being apertured for admitting air thereto, the discharge end of said throat extending beyond the apertured portion of said wall, a plurality of partition plates dividing said discharge portion into a plurality of flat alternate'passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their discharge and intake ends with the furnace and said mixing chamber respectively, said air passages communicating with the atmosphere and arranged to discharge into the furnace through said discharge portion, a plurality of walls dividing said passages for the mixture of fuel and air into groups, a wall separating the air passages from said mixing chamber and a plurality of deflector members pivotally mounted in said mixing chamber and arranged to variably restrict and direct the discharge of pulverized fuel from said mixing chamber through the plurality of passages for the mixture of fuel and air of the several groups.

5. In combination with a furnace having a firing opening in a wall thereof, a pulveriaed fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising a mixing chamber, a rearward tubular member delivering pulverized fuel to and through said mixing chamber, means for agitating the pulverized fuel as the same is propelled into and through said mixing chamber, means arranged for the admission ,pf air to said mixing chamber, a discharge forward portion, a plurality of partition plates dividing said discharge forward portion into a plurality of flat, horizontally disposed alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their forward and rearward ends with the furnace and said mixing chamber respectively, said air passages communicating with atmosphere and at their forward ends arranged to discharge into the furnace at the forward end of said discharge portion, a plurality of longitudinally extending, vertically aligned walls dividing said passages for the mixture of fuel and air into groups and a transversely extending vertical wall separating the air passages from said mixing chamber.

6. In combination with a furnace having a liring opening in a wall thereof, a pulverized fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising a mixing chamber, a tubular member delivering pulverized fuel to and through said mixing chamber, means for agitating the pulverized fuel as the same is propelled into and through said mixing chamber, a discharge portion, a plurality of partition plates dividing said discharge portion into a plurality of fiat alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their discharge and intake ends with the furnace and said mixing chamber respectively, said air passages communicating with the atmosphere and arranged to discharge into the furnace through said discharge portion, a plurality of walls dividing said passages for the mixture of fuel and air into groups, and a wall separating the air passages from said mixing chamber.

'7. In combination with a furnace having a firing opening in a wall thereof, a pulverixed fuel burner arranged to discharge fuel into the furnace through said firing opening, said pulverized fuel burner comprising a mixing chamber, a tubular member delivering pulverized fuel to and through said mixing chamber, means for agitating the pulverized fuel as the same is propelled into and through said mixing chamber, a discharge portion, a plurality of partition plates dividing said discharge portion into a plurality of flat alternate passages for air and for a mixture of fuel and air, said passages for the mixture of fuel and air communicating at their discharge and intake ends with the furnace and said mixing chamber respectively, Vsaid. air passages communicating with the atmosphere and arranged to discharge into the furncae through said discharge portion, a plurality of walls dividing said passages for the mixture of fuel and air into groups, a wall separatng the air passages from said mixing chamber, and a plurality of deflector members pivotally mounted in said mixing chamber and arranged to variably restrict and direct the discharge of pulverized fuel from said mixing chamber through the plurality of passages for the mixture of fuel and air of the several groups.

MELLEN C. M. HATCH. 

